Field of the Invention
The present disclosure relates to an image forming apparatus that determines a type of a recording material and sets an image forming condition on the recording material in accordance with a result of the determination.
Description of the Related Art
Hitherto, there have been some image forming apparatuses, such as a copier and a printer, that include a sensor which performs detection for information about a physical characteristic (e.g., a grammage or a surface property) of a recording material and determine a type of the recording material from a result of the detection performed by the sensor. In such apparatuses, an image forming condition such as a transfer condition (e.g., a transfer voltage or a conveyance speed of the recording material at a time of being transferred) or a fixing condition (e.g., a fixing temperature or a conveyance speed of the recording material at a time of being fixed) is set in accordance with a result of the determination of the type of the recording material, so that an image quality is refined.
In Japanese Patent Laid-Open No. 2016-102867, by focusing on a characteristic of a recording material varying in accordance with a moisture content contained in the recording material, a detection result obtained by a sensor is corrected based on a moisture content in air, which is obtained from a temperature and a humidity around an image forming apparatus. For example, when the moisture content in the air is high under a high-temperature and high-humidity environment, the moisture content contained in the recording material is also expected to be high. Then, when the moisture content contained in the recording material is high, a grammage of the recording material increases in accordance with the moisture content. The image forming apparatus is able to determine the grammage of the recording material more accurately by correcting the detection result obtained by the sensor while considering such a moisture content of the recording material.
However, in a case where image formation is performed in a state where the moisture content contained in the recording material is high, particularly when the recording material is heated through processing of fixing an image, the recording material is likely to be curled as the moisture contained in the recording material evaporates. Thus, a configuration in which a heater is provided in a part of a sheet feeding port to heat the recording material so that moisture absorption of the recording material is suppressed and curl of the recording material is suppressed is known.
With this configuration, the temperature and the humidity around the image forming apparatus are greatly different from a temperature and a humidity near the sheet feeding port, so that it is difficult to estimate the moisture content of the recording material based on the moisture content in the air as in Japanese Patent Laid-Open No. 2016-102867. As a result, accuracy of determination of the grammage of the recording material is lowered and the image forming condition is erroneously set, so that there is a possibility that an image quality is deteriorated.